This invention relates to an improved process for the preparation of fluid, highly basic magnesium sulfonates useful as lubricants for internal combustion engines and as diesel fuel additives.
Highly basic magnesium sulfonates are known to be particularly effective additives for internal combustion engine lubricating oils and for diesel fuels. In this context, the term "highly basic" refers to sulfonates containing an amount of magnesium substantially in excess of that required to form a neutral sulfonate. Other terms which have been used to describe such sulfonates include overbased, superbasic and hyperbasic.
Many, many processes are known for preparing fluid, highly basic magnesium sulfonates. See, e.g., U.S. Pat. Nos. 3,492,230; 3,524,814; 3,609,076; 3,629,109; 3,865,737; and the numerous patents cited therein. While many of these prior art processes and patents claim to be suitable for commercial scale production of highly basic magnesium sulfonates, few highly basic magnesium sulfonates are available on the market.
Accordingly, there is still a need for improved, commercially viable processes for the preparation of commercial scale batches of fluid, highly basic magnesium sulfonates, especially processes which have a high utilization of magnesium and which produce sulfonates that have a high total base number (TBN), of about 385 or more, a low viscosity, an absence of haze and sediment, and good stability under engine use conditions.